Senior Member of the Staff
Department of Periodontology
Lecturer in Periodontology,
Harvard School of Dental Medicine
email:
Royal College of Surgeons, UK, L.D.S., 1970, Dental Surgery
University of London, UK, B.D.S., 1971, Dental Surgery
Royal College of Surgeons, UK, D.D.P.H., Dental Public Health
The overall goals of the Department are:
1. To examine the microbial ecology of the oral cavity;
2. To examine the effects of different periodontal therapies on clinical and microbial parameters of disease; and
3. To develop and improve laboratory techniques to examine microbial and host factors associated with periodontal diseases.
The oral cavity presents numerous different soft and hard tissue surfaces for colonization by complex mixtures of microbial species. Studies of microbial ecology, disease initiation and progression, as well as the effects of therapy on the oral microbiota have been hampered by the limited numbers of biological samples and species that could be identified using traditional microbiological techniques. For example, a well-trained investigator might be able to identify 50 colonies in each of 50– 100 samples of subgingival plaque in a year, using routine identification methods. To overcome this limitation, investigators at Forsyth developed the "checkerboard" DNA-DNA hybridization technique in the early 1990s. This technique is able to analyze 28 oral biofilm samples (e.g., one from each tooth) for their content of 40 bacterial species on a single nylon membrane, providing 1,120 bacterial counts. The technique is used in numerous laboratories in the world and is extremely high throughput. In the Forsyth Department of Periodontology alone, over 150,000 oral microbial samples have been analyzed in the last 10 years. The use of this technique facilitated studies of microbial ecology that defined subgingival microbial complexes and elucidated site-level and host-level factors that strongly influence the composition of the microbiota. The technique also permitted the identification of periodontal pathogens by determining differences in the composition of the subgingival microbiota between health and disease and examining the effect of treatment on subgingival species. The technique also permitted examination of the effect of different forms of periodontal therapy on the microbial composition of subgingival biofilms as well as studies of the microbial succession that occurs during the development of intra-oral biofilms in periodontally healthy, periodontitis and denture-wearing edentulous subjects.
Recently, Forsyth investigators pioneered the use of the multiple displacement amplification (MDA) technique for the examination of the oral microbiota. This technique uniformly amplifies samples of genomic DNA with minimum amplification bias. It is being used for the preparation of abundant DNA for DNA probe analysis, the amplification of small samples (such as samples from root canals or surgical procedures) and provision of archival DNA amplified from "precious" samples from unusual clinical cases.
One limitation of the original "checkerboard" technique is that the technique employed DNA probes made for cultivable species only. In recent years, investigators have used consensus primers to the 16S rRNA gene and PCR to amplify DNA directly from subgingival plaque samples. The resulting products were cloned into Escherichia coli and the inserts were sequenced. The results indicated that as many as 700 taxa may be detected in the oral cavity, about 400 in subgingival plaque, most of which were "uncultivable" or at least not recognized. Oligonucleotide probes may be designed to specific sequences of the 16S rDNA of the as yet uncultivated species. In order to provide quantitative data, a method has been devised to use the oligonucleotide probes to such species in a direct checkerboard format. One of the problems in using oligonucleotide probes for direct checkerboard hybridization is that they are 100–1000 times less sensitive than whole genomic probes for the quantification of taxa in individual biofilm samples. Thus, up until now, the desired sequences in a sample had to be amplified and labeled by PCR prior to reverse capture hybridization. We have coupled the MDA technique with the oligonucleotide probes to as yet uncultivated species to overcome this limitation. The MDA technique is able to uniformly amplify microbial DNA from small samples 1,000 to 10,000 fold providing sufficient DNA for the less sensitive oligonucleotide probes to detect and quantify.
In parallel with the development of high throughput techniques to quantify the oral microbiota, the Department has been active in developing high throughput techniques to assess the host response to oral infectious processes. The first of these was the development of checkerboard immunoblotting for the detection of antibody to a wide range of bacterial species in multiple serum samples simultaneously. This technique was extended to detect antibody to multiple species in multiple samples of gingival crevice fluid (GCF) on a single support membrane. Once more this technique is being employed in many laboratories in different countries.
More recently, a new checkerboard immunoblotting technique has been developed in our laboratory to simultaneously quantify cytokines or other host markers in multiple samples of GCF or other body fluids such as serum or saliva. The sensitivity of such assays is remarkable in that the technique can detect picog rams of the target substance in sample volumes of less than 1 microliter. The development of the high throughput methods of microbial analysis coupled with high throughput measures of markers of the host response will enable studies of host parasite interaction during disease and as a result of therapy that are unprecedented in human biology.
In recent decades there have been major advances in our understanding of the microbiology of periodontal diseases. This is due, in large part, to the development of rapid, molecular techniques that facilitate examination of the wide range of fastidious bacterial species that colonize subgingival biofilms as described above. Studies in this department using the checkerboard DNA-DNA hybridization technique have suggested probable pathogens and confirmed the role of the designated periodontalpathogens, A.actinomycetemcomitans, P. gingivalis and T. forsythia in the initiation and progression of periodontal infections. This technique has also facilitated our examination of early biofilm development on the teeth and soft tissues of healthy, periodontitis, Sjogren's and edentulous subjects.
These studies clearly demonstrated bacterial succession during biofilm development as well as the influence of surface and the nutrient bulk fluid, saliva or GCF, on this process. For example, in a study examining plaque re-development in the absence of tooth or denture cleaning, plaque samples were taken from the dentures of fully edentulous subjects, as well as the teeth of periodontally healthy and periodontitis subjects immediately after tooth or denture cleaning, and after one, two, four and seven days. Plaque development on the dentures of the edentulous subjects occurred less rapidly than on the teeth of either the periodontally healthy or periodontitis subjects. Clearly, the absence of a subgingival environment, gingival tissues and the nutrient, GCF, impacts the rate of plaque development. An interesting finding from this study was that the periodontal pathogens, A.actinomycetemcomitans and P. gingivalis, which are thought to disappear from the oral cavity after removal of all the teeth, were evident in this edentulous population. In a study of subjects with Sjogren's Syndrome, who have reduced salivary flow rates, we demonstrated that supra- and subgingival plaque levels were lower in these subjects compared to periodontally healthy and periodontitis subjects, although their periodontal disease status was similar to that of the periodontitis subjects. We have also demonstrated that the microbiota of the oral soft tissues differs from that found on the teeth. In addition, the microbiota of the saliva and tongue differs from that found on the other oral soft tissues. A crucial recognition has been that dental plaque is a biofilm, a living film that provides structure, protection from host and therapies, as well as permitting communication and passage of genetic material among resident species. The nature of some of the associations among bacterial species in the subgingival biofilm has been delineated. Previous and ongoing studies in the department have examined the nature of the relationship of bacterial species within the subgingival biofilm. Examination of over 13,000 subgingival plaque samples for the levels of 40 subgingival species using cluster analyses and community ordination demonstrated that species could be grouped into different complexes and that the complexes related differently to one another.
These studies indicated that some bacterial communities are associated with health, while others, such as the "red complex" consisting of P.gingivalis, T. forsythia and T. denticola are thought to be pathogenic reaching major proportions in the zone adjacent to the periodontal pocket wall. We have also examined factors affecting the composition of the subgingival microbiota including pocket depth, inflammatory mediators and host level factors such as smoking, genetic background, obesity, Sjogren's Syndrome and geographic location.
The improved understanding of the periodontal microbiota and the effects of different therapies on different segments of the microbiota have led to changes in the approaches used to treat periodontal infections including the use of selected antibiotics both locally and systemically. Previous studies performed in this department, together with studies in the literature, have indicated that the use of systemically administered antibiotics can significantly improve the clinical outcome after therapy. For example, a recently completed study in which we collaborated with the University of Goteborg, Sweden, indicated that subjects receiving the combination of systemically administered amoxicillin and metronidazole with or without periodontal surgery exhibited greater clinical benefits than subjects in whom antibiotics were not employed. Improvement in clinical parameters is accompanied by a significant reduction in the su bgingival bacteria, particularly the pathogenic members of the red and orange complexes, which is greater in subjects receiving antibiotics than those not receiving these agents.
One of the major research activities in the Department of Periodontology is to better understand the effects of different periodontal therapies in order to provide the most beneficial therapy for a specific periodontal infection. Two randomized clinical studies are currently being carried out in the department examining different therapies alone and in combination for the treatment of periodontitis. In the first, the benefits of repeated professional supragingival plaque removal and systemically administered metronidazole are being evaluated. We, and others, have shown that repeated professional supragingival plaque removal resulted in improved clinical parameters and beneficial changes in the subgingival microbiota. Further, we have also demonstrated the beneficial effects of systemically administered metronidazole to treat periodontal infections. In this ongoing longitudinal study, the effects of both of these therapies, alone and in combination, are being evaluated, with the hypothesis that the two therapies together should provide an added benefit over and above that obtained by either therapy alone. Subjects, randomized to the different treatment groups are clinically and microbiologically monitored at baseline and three, six, 12, 18 and 24 months after therapy.
We are also evaluating the effect of cigarette smoking on oral health and treatment outcomes. Previous studies have indicated that smokers have more periodontal disease than non-smokers and that these individuals have a higher percentage of periodontal sites colonized by periodontal pathogens. In an ongoing study, the effects of different treatment regimes are being examined in smokers and non-smokers. Three different treatment modalities: scaling and root planing (SRP) only; SRP plus systemically administered metronidazole; or SRP plus systemically administered metronidazole and amoxicillin as well as delivery of local antibiotics in deep periodontal pockets, will be administered to equal numbers of smokers and non-smokers. Subjects, randomized to the different treatment groups are clinically and microbiologically monitored at baseline and 3, 6, 12, 18 and 24 months after therapy. It is hypothesized that the antibiotic therapies will provide a greater benefit to smokers and that the combined antibiotic therapy will provide the greatest benefit.
We are also examining the effect of a combined treatment consisting of SRP, systemically administered amoxicillin and metronidazole, locally delivered antibiotics and professional supragingival plaque removal, in subjects who are "refractory" to standard periodontal therapies. These subjects, who have received multiple previous therapies, generally have low levels of periodontal pathogens, but are unable to cope even with lowered levels of these species. The combined therapy has proved to be successful in the majority of the refractory patients for up to several years post therapy.
Periodontal diseases are among the most common infectious diseases affecting mankind. The bacteria that cause these diseases reside in complex communities called dental plaque that occur at or below the gingival (gum) margin. Some bacterial species in these communities lead to destruction of the supporting structures of the teeth (the periodontal ligament, cementum, gingiva and alveolar bone). These bacteria also may affect other parts of the body increasing the risk for cardiovascular disease, stroke and low birth-weight babies. Past and current studies performed in this Department have helped to define the etiologic agents of periodontal diseases, the inter-relationships among plaque bacteria, the composition of biofilms on oral soft tissues, the influence of surface and oral fluids on plaque development, the natural history and progression of periodontal diseases as well as examination of different therapeutic modalities to control these infections. Other studies have indicated that specific species in the subgingival plaque exist in complexes or communities and defined the relationship of these communities to local tissue status, host genetic and environmental factors such as cigarette smoking. The Department has initiated a series of studies to determine the effect of different therapeutic approaches on the composition of the bacteria in dental plaque. The results of these studies will indicate how periodontal therapies affect the subgingival microbiota and will clarify the importance of ecological relationships in the control of periodontal infections.
Teles RP, Sakellari D, Konstantinidis A, Socransky SS, Haffajee AD. (2009) Application of the checkerboard immunoblotting technique to the quantification of host biomarkers in gingival crevicular fluid. J. Periodontol. 80(3):447-456.
Haffajee AD, Socransky SS. (2009) Relation of body mass index, periodontitis and Tannerella forsythia. J. Clin. Periodontol. 36(2):89-99.
Haffajee AD, Yaskell T, Torresyap G, Teles R, Socransky SS. (2009) Comparison between polymerase chain reaction-based and checkboard DNA hybridization techniques for microbial assessment of subgingival plaque samples. J. Clin. Periodontol. 36(8):642-649.
Teles RP, Likhari V, Socransky SS, Haffajee AD. (2009) Salivary cytokine levels in subjects with chronic periodontitis and in periodontally healthy individuals: a cross-sectional study. J. Periodontal Res. 44(3):411-417.
Haffajee AD, Teles RP, Patel MR, Song X, Veiga N, Socransky SS. (2009) Factors affecting human supragingval biofilm composition. I. Plaque mass. J. Periodontal Res. 44(4):511-519.
Haffajee AD, Teles RP, Patel MR, Song X, Yaskell T, Socransky SS. (2009) Factors affecting human supragingival biofilm composition. II. Tooth position. J. Periodontal Res. 44(4):520-528.
Haffajee AD, Socransky SS, Patel MR, Song X. (2008) Microbial complexes in supragingival plaque. Oral Microbiol. Immunol. 23(3):196-205.
Teles RP, Patel M, Socransky SS, Haffajee AD. (2008) Disease progression in periodontally healthy and maintenance subjects. J. Periodontol. 79(5):784-794.
Bogren A, Teles RP, Torresyap G, Haffajee AD, Socransky SS, Wennstrom JL. (2008) Locally delivered doxycycline during supportive periodontal pherapy: a 3-year study. J. Periodontol. 79(5):827-835.
Teles FR, Haffajee AD, Socransky SS. (2008) The reproducibility of curet sampling of subgingival biofilms. J. Periodontol. 79(4):705-713.
Haffajee AD, Patel M, Socransky SS. (2008) Microbiological changes associated with four different periodontal therapies for the treatment of chronic periodontitis. Oral Microbiol. Immunol. 23(2):148-157.
Teles F, Haffajee AD, Socransky SS. (2007) Multiple displacement amplification as an aid in checkerboard DNA-DNA hybridization. Oral Microbiol. Immunol. 22(2):118-125.
Haffajee AD, Torresyap G, Socransky SS. (2007) Clinical changes following four different periodontal therapies for the treatment of chronic periodontitis: 1-year results. J. Clin. Periodontol. 34(3):243-253.
Teles RP, Bogren A, Patel M, Wennstrom JL, Socransky SS, Haffajee AD. (2007) A three-year prospective study of adult subjects with gingivitis II: microbiological paramaters. J. Clin. Periodontol. 24(1)7-17.
Haffajee AD. (2006) Systemic antibiotics: to use or not to use in the treatment of periodontal infections. That is the question. J. Clin. Periodontol. 33(9):359-361.
Colombo AV, Silva CM, Haffajee A, Colombo APV. (2006) Identification of oral bacteria associated with crevicular epithelial cells from chronic periodontitis lesions. J. Med. Microbiol. 55(Pt. 5):609-615.
Quirymen M, Vogels R, Peeters W, van Steenberghe D, Naert I, Haffajee A. (2006) Dynamics of initial sub-gingival colonization of 'pristine' peri-implant pockets. Clin. Oral Implants Res. 17(1):25-37.
Haffajee AD, Teles RP, Socransky SS. (2006) Association of Eubacterium nodatum and Treponema denticola with human periodontitis lesions. Oral Microbiol. Immunol. 21(5):269-282.
Haffajee AD, Socransky SS. (2006) Introduction to microbial aspects of periodontal biofilm communities, development and treatment. Periodontol. 2000 42(1):7-12.
Teles RP, Haffajee AD, Socransky SS. (2006) Microbiological goals of periodontal therapy. Periodontol. 2000 42(1):180-218.
Haffajee AD, Teles RP, Socransky SS. (2006) The effect of periodontal therapy on the composition of the sub-gingival mcrobiota. Periodontol. 2000 42(1):219-258.
Lopez NJ, Socransky SS, Da Silva I, Japlit MR, Haffajee AD. (2006) Effects of metronidazole plus amoxicillin as the only therapy on the microbiological and clinical parameters of untreated chronic periodontitis. J. Clin. Periodontol. 33(9):648-660.
Quirynen M, Vogels R, Peeters W, van Steenberghe D, Naert I, Haffajee A. (2006) Dynamics of initial subgingival colonization of "pristine" peri-implant pockets. Clin. Oral Implant Res. 17(1):25-37.
Haffajee AD, Japlit M, Bogren A, Kent RL Jr, Goodson JM, Socransky SS. (2005) Differences in the subgingival microbiota of Swedish and USA subjects who were periodontally healthy or exhibited minimal periodontal disease. J. Clin. Periodontol. 32(1):33-39.
Carvalho LH, D'Avila G, Leao A, Goncalves C, Haffajee AD, Socransky SS, Feres M. (2005) Scaling and root planing, systemic metronidazole and professional plaque removal in the treatment of chronic periodontitis in a Brazilian population. II. Microbiological results. J. Clin. Periodontol. 32(4):406-411.
Haffajee AD, Socransky SS. (2005) Microbiology of periodontal diseases: Introduction. Periodontol. 2000 38(1):9-12.
Socransky SS, Haffajee AD. (2005) Periodontal microbial ecology. Periodontol. 2000 38(1):135-187.
Quirynen M, Alsaadi G, Pauwels M, Peeters W, Haffajee A, van Steenberghe D, Naert I. (2005) Microbiological and clinical outcomes and patient satisfaction for 2 treatment options in the edentulous lower jaw, after 10 years of function. Clin. Oral Implants Res. 16(3):277-287.
Mager DL, Haffajee AD, Devlin PM, Norris CM, Posner MR, Goodson JM. (2005) The salivary microbiota as a diagnostic indicator of oral cancer: a descriptive, non-randomized study of cancer-free and oral squamous cell carcinoma subjects. J. Transl. Med. 3(1):1-8.
Ricardo Teles,D.D.S., D.M.Sc., Director of the Center for Clinical and Translational Research
Marie Letteri, Clinic Manager
Chris Roberts, Research Dental Hygienist
Nancy Veiga, Research Dental Hygienist
Ana Bruk, Research Dental Assistant
Lynn Martin, Research Assistant III
Tina Yaskell, Staff Associate
Michele Patel, Research Assistant I
Lucy Song, Research Assistant I
Flavia Teles, ,D.D.S., D.M.Sc.,Research Dentist
Emilio Arguello,D.D.S., D.M.Sc., Staff Associate
